There is no rational argument against it.
There is no rational argument for SSM. Marriage is just regulations imposed on people who might seek monogamous sexually reproduction. Couples do not need to be married to express love or to be happy or to be sexually gratified.
Lack of marriage privileges for same-sex couples is a calamity because marriage also grants special socio-economic privileges. If you look at the income data, the only family demographic that earns more than median household income is dual income married couples. The current system screws all unmarried people to protect the sanctity of "traditional" single-income married households. Unmarried people include homosexuals in most instances.
I'm empathetic to the plight of gay couples, but SSM does not fix the problem nor does it represent civil rights victory. It is a silly politically-indulgent skirmish for small-minded people who are eager to avoid dealing with our real problems.
Our real problems? Such as? I don't see how citizens being treated as scum is not a problem.
